Prior to the present invention, as shown by Heath et al., U.S. Pat. No. 3,847,867, assigned to the same assignee as the present invention, polyetherimides were made by effecting reaction between aromatic bis(etheranhydride) and organic diamine in the presence of an organic solvent. Although valuable injection moldable polyetherimides can be made by the Heath et al. procedure, in many instances the glass transition temperature of the products, such as 220.degree. C., are sometimes too high for particular applications. In addition, polyetherimides are often tinted and therefore are unsuitable for applications requiring transparent material.
The present invention is based on our discovery that transparent polyimides having significantly lower Tgs can be made by effecting reaction between aromatic bis(etheranhydride), such as 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propanedianhydride-(BPADA) and organic diamine having the formula, ##STR1## where n is an integer having a value of from 1-5 inclusive.